A common treatment often utilized in ophthalmic and vitreoretinal surgery is that of directing laser energy to a surgical site, the targeted surgical site typically being proximate a patient's retina and the surrounding vitreous. Such a surgery is called an endo-ocular photocoagulation procedure, and may be indicated for reattachment of a detached retina, for cauterization of a ruptured blood vessel, for repair of a surgical wound, for removal of defective tissue or vitreous material, and the like.
In order to conduct the endo-ocular photocoagulation procedure, the surgeon must utilize a microsurgical laser probe to deliver the laser energy to the surgical site. The microsurgical laser probe typically comprises a handle with a small cylindrical sleeve, or tip, projecting from the distal end of the handle. An optical fiber element is connected at the proximal end to a laser source, and the fiber is carried through the microsurgical laser probe and into the cylindrical sleeve. The optical fiber element is positioned adjacent the distal end of the cylindrical sleeve in order to effectively deliver laser energy to the intended surgical site.
Prior to beginning the surgery, the surgeon must ascertain and select the appropriate size and type of microsurgical laser probe tip to be used. Currently, microsurgical laser probe tips are available in three predominant sizes: 20 gauge (0.0360 inches), 23 gauge (0.0255 inches), and 25 gauge (0.0205 inches). For smaller gauge probe tips, the use of an appropriately sized trocar cannula is indicated. The trocar cannula is used to pierce the patient's ocular tissue and, thereafter, to provide a passageway for the insertion and support of the probe tip, to prevent the probe tip from bending at the point of entry into the eye, to reduce tearing of the ocular tissue at the insertion point, and to act as a guide channel for the probe tip into the eye. Accordingly, 23 and 25 gauge tips are nearly always used in association with trocar cannulae; whereas, because of relatively larger size and stiffness, 20 gauge tips do not typically require use of trocar cannulae.
When using a 20 gauge probe tip, the surgeon pierces or punctures the ocular tissue in a selected location, inserts the probe tip to the appropriate depth, angle, and position, and begins the endo-ocular photocoagulation procedure. When using either a 23 or 25 gauge probe tip, the surgeon first pierces or punctures the ocular tissue in a selected location with a trocar cannula and positions it on the eye. Thereafter, the 23 or 25 gauge probe tip is passed through the trocar cannula and into the eye to the appropriate depth, angle, and position. Thereafter, the endo-ocular photocoagulation procedure may be conducted.
It is instructive to note that, in order to be most surgically effective, the laser energy should be delivered as nearly perpendicular to the targeted surgical area as possible. Due to positioning of the microsurgical laser probe tip, and the positioning of any associated trocar cannula that may be utilized by the surgeon during the procedure to direct the microsurgical laser probe into the eye, it is most often the case that the surgical site is either inaccessible or located disadvantageously for proper application of laser energy.
In order to solve this problem, curved tips have been introduced for use in association with above-described microsurgical laser probes. Use of such curved tips is advantageous in comparison to use of a straight tip in better orienting the probe tip adjacent the surgical site without need to withdraw and reposition the laser probe, and without the associated secondary punctures of the eye; and, further, in providing for a greater range of coverage inside the eye. Disadvantageously, such curved tips are of fixed curvature and, depending upon the relative diameters of the tip and the associated trocar cannula, sometimes cannot be inserted through straight trocar cannulae. Furthermore, if a different curvature is required in order to properly target the surgical site, the instrument must be withdrawn, and the entire probe must be replaced with one having a tip of appropriate curvature, and the initial wound site re-intruded. Such process is, of course, less than optimal for both patient and surgeon.
To overcome these disadvantages, others have introduced adjustable, directional laser probes that are capable of being adjustably manipulated toward a target surgical site; thereby, seeking to avoid some of the above-referenced disadvantages, while seeking to better direct laser energy to the targeted surgical area. Some such devices are discussed below, and their referenced disclosures are incorporated herein by reference.
U.S. Pat. No. 6,572,608 to Lee et al. provides a probe with a handle and a tubular sleeve. The distal portion of the tubular sleeve has an optical fiber projecting therefrom that can be caused to bend relative to the sleeve by manual manipulation of a mechanism on the probe handle, as the optical fiber is enclosed within a pre-formed curved memory material, such as Nitinol. Disadvantageously, whenever exterior parts of a device move, there is a risk that foreign materials can become lodged within or between those exterior moving parts. Because the Lee et al. design utilizes moving, exterior mechanical parts which move relative to one another within the eye, there is an attendant risk that tissue may become snagged or tangled therebetween. Additionally, when deploying the tip outwardly, the surgeon must carefully ascertain where the tip is located relative to the intended target surgical site in order to prevent puncturing the back of the eye. The surgeon must continually keep a finger positioned on the extension/retraction mechanism to control deployment and retraction of the probe tip, while simultaneously controlling insertion and withdrawal of the probe tip. In other words, the surgeon must undertake a two-step, iterative targeting procedure wherein he/she must withdraw or insert the probe tip, adjust the tip curvature, and repeat until the targeted area can be appropriately accessed. This is a complex, non-intuitive surgical manipulation of the probe instrument, with possible damage resulting to the retina or other ocular tissue.
U.S. Pat. No. 6,984,230 to Scheller et al., a continuation-in-part of U.S. Pat. No. 6,572,608 to Lee et al., further provides that a tubular member carrying the optical fiber may be deployed outwardly from the sleeve.
Disadvantageously, and as with U.S. Pat. No. 6,572,608 to Lee et al., such design utilizes moving, exterior mechanical parts which move relative to one another within the eye, with an attendant risk that tissue may become snagged or tangled therebetween. Additionally, and as with Lee et al., when deploying the tip outwardly, the surgeon must carefully ascertain where the tip is located relative to the intended target surgical site in order to prevent puncturing the back of the eye. The surgeon must continually keep a finger positioned on the extension/retraction mechanism to control deployment and retraction of the probe tip, while simultaneously controlling insertion and withdrawal of the probe tip. In other words, the surgeon must undertake a two-step, iterative targeting procedure wherein he/she must withdraw or insert the probe tip, adjust the tip curvature, and repeat until the targeted area can be appropriately accessed. This is a complex, non-intuitive surgical manipulation of the probe instrument, with possible damage resulting to the retina or other ocular tissue.
In order to overcome such disadvantages, U.S. Pat. No. 7,766,904 to McGowen, Sr. et al. provides a laser probe capable of functioning in both straight and curved forms. The probe includes an elongated hand piece and rigid cannula affixed thereto to prevent relative translational movement between them. A pre-curved optical fiber inside a memory material, such as Nitinol, extends through the hand piece and cannula, and a slidable button is affixed to the optical fiber through use of a cooperating rigid sleeve. The relative motion of the button with respect to the handle is tied, both visually and physically, to the relative extension, and the resulting curvature, of the optical fiber, with the intended result being avoidance or minimization of damage to the retina or other ocular tissue. Unfortunately, many of the same disadvantages may be seen; to wit, such design utilizes mechanical parts which move relative to one another within the eye, with an attendant risk that tissue may become snagged or tangled therebetween. Further, when deploying the tip outwardly, the surgeon must still guess, or follow additional procedures to ascertain, where the tip is located relative to the intended target surgical site. The surgeon must continually keep a finger positioned on the extension/retraction mechanism to control deployment and retraction of the tip, while simultaneously controlling insertion and withdrawal of the probe tip (the two-step, iterative targeting procedure described above). This results in a complex, non-intuitive surgical manipulation of the instrument, with possible damage resulting to the retina or other ocular tissue.
United States Patent Application 2010/0004642 A1 by Lumpkin proposes a surgical laser probe wherein a hand piece carries an optical fiber through and into a stainless steel tube, the distal end of which carries a length of polyimide bendable tube. The optical fiber is coterminous with the free end of the polyimide tube. A slidable element is installed within a slot in the hand piece and secured to a length of pre-curved Nitinol wire. As the slideable wire element is moved toward the distal end of the hand piece, the Nitinol wire is advanced into the free end of the polyimide tube, increasingly bending the tube and optical fiber away from the longitudinal axis of the stainless steel tube and hand piece. Disadvantageously, this design bends the optical fiber tip about a single point; thus, having a relatively small local radius of curvature, resulting in a relatively large, straight-line offset of the tip. Accordingly, the surgeon may not be able to reach the targeted surgical site due to insufficient curvature of the tip. Furthermore, a small local radius of curvature can, in some cases, reduce or interfere with laser transmission if the radius is below the value recommended by the manufacturer of the optical fiber.
As was discussed above, probe tips having a fixed curvature sometimes cannot be inserted through straight trocar cannulae, depending upon the relative diameters of the tip and the associated trocar cannula. For example, many trocar cannulae are manufactured according to proprietary or customized specifications, such that a trocar cannula manufactured by one company will not be fully compatible with surgical solutions provided by another company. Accordingly, a probe tip providing fixed curvature may be compatible with one model or size of trocar cannula, but not with another. An exemplary solution is proposed in U.S. Pat. No. 7,909,816 to Buzawa, which provides a rigid probe for use with a rigid cannula, the probe having an outside diameter smaller than the inside diameter of the cannula, the probe having one or more sections comprising radii of curvature selected to ensure passage of the probe through the length of the cannula without interference. This is seen to be disadvantageous not only in probe tip manufacture, but also in adding to the complexity of surgical probe entry into and removal from the cannula, and in manipulation and movement of the probe tip during a procedure.
Yet additionally, in most surgeries, one or more additional surgical tool(s), such as a surgical-site illumination instrument, may be needed. Such additional surgical instruments may require additional penetrations into the eye tissue, in which case the recovery time for the patient may be increased, and the risk of complications may likewise be increased.
In an attempt to reduce the need for such additional instruments, particularly those requiring a separate intrusion into the eye, laser energy surgical probes have been designed to deliver both laser energy for treatment and illumination energy, such as for visualization of the targeted surgical site, using a single probe. Thus, only a single penetration into the eye may be required for visualization of the targeted surgical area, as well as for delivery of laser energy to the area to accomplish the surgery.
As such, it is clear that there is an unmet need for an ophthalmic surgical device capable of delivering illumination energy and/or laser energy for treatment of a patient's eye via a single wound site, while maintaining a small diameter probe for reducing unwanted injury to the eye.
Accordingly, what is still needed is an adjustable, directional laser probe for endo-ocular photocoagulation procedures providing, in some embodiments, a fixed curvature laser probe tip that flexes when penetrating a trocar cannula; and in other embodiments, a variable curvature laser probe tip that is operable between straight and curved tip configurations, and that may deliver one or both of laser energy for treatment and illumination energy for visualization of the targeted surgical site, all using a single probe, and all while eliminating or reducing the above-referenced disadvantages in accordance with the detailed disclosure of the inventive subject matter set forth hereinbelow. It is to the provision of such probes that the present invention is directed.